The present invention relates to the treatment of Imported Fire Ants. In particular, the present invention relates to a method and an apparatus for the eradication of Imported Fire Ants.
Since the introduction of Solenopsis saevissima into the United States at Mobile, Ala., in 1918, several other species of the South American ant, of the Genus Solenopsis, have subsequently been brought into the country. For example, Solenopsis invicta came in from Argentina or Bolivia in about 1930. This species, being the most voracious of the genus, drove out and killed the Solenopsis geminata and Solenopsis saevissima. Solenopsis invicta is known to kill and eat chickens, calves, and piglets. They also store grain, such as soybeans, as well as the remains of their animal victims. They are known to consume an average of six to eight bushels of soybeans per acre in those fields with normal infestation. They attack any living thing that invades their established territory surrounding their nesting mounds. For example, in 1979, one Georgia country hospial treated some 28,500 human ant sting victims in this one year alone. Solenopsis has also killed or driven out of their territories countless numbers of helpful species of insects, particularly other beneficial or harmless ant species. Of the five recognized species of fire ants in the United States, Solenopsis invicta, the Red Imported Fire Ant, and Solenopsis richteri, the Black Imported Fire Ant, are the two most economically important.
To date, more than 300 million acres of crop land, pasture land, school grounds, lawns, recreation areas, etc., throughout the entire southern portion of the United States and Puerto Rico have been infested by the Imported Fire Ant, with many millions of acres rendered useless. According to United States Department of Agriculture estimates, Solenopsis is continuing to spread outward at the rate of about thirty (30) miles per year, is expected to eventually extend as far north as New York, and to completely cover the Pacific coast states.
The United States Department of Agriculture also estimates an annual yearly loss to agriculture of several billions of dollars. For example, in 1981, the loss of soybeans in Texas alone amounted to some $485 million. In Florida the annual loss of soybeans amounts to $245 million at this time. In 1986, the United States Department of Agriculture presented data showing the economic impact of the Imported Fire Ant on the Florida citrus industry to be as follows: (1) replacement of Navel Orange trees, $77.00 per acre; (2) replacement of Hamlin Orange trees, $146.20 per acre; and (3) replacement of Grapefruit trees, $207.20 per acre. Additionally, it is estimated that the loss of potato crops in Florida alone is some 36% of the total crop. Of course, other states will have similar statistics.
The current state of the art of Imported Fire Ant control is basically the same as it has been from the beginning, i.e., chemical control; with the majority of the poison baits used being supplied by and/or subsidized by the government. The most effective chemical control agent was Mirex, dodecachloroocta-hydro-1,3,4-metheno-2H-cyclobuta(cd)pentalene. However, Mirex is a proven carcinogenic agent and has an Acute Oral LD.sub.50 of 306 mg./kg. Mirex was banned by the Federal Government in 1978.
Currently, the government is approving for use American Cyanamid Company's Amdro, tetrahydro-5,5,-dimethyl-2(1-H)-pyrimidinone[3-[4-(trifluoromethyl)phenyl] -1-[2-[4-trifluoromethyl]phenyl]ethenyl]-2-propenyl-idene]hydrazone, which is another amidino-hydrazone of the organo-fluorine group. Amdro is very limited in its effectiveness and its use, since it can only be applied when climatic conditions are extremely favorable. The primary problem with all poison baits is the fact that they are indiscriminate killers and have eliminated useful and helpful insects, including ants, where they are used. It has become the general consensus of opinion of the recognized experts in the field of Imported Fire Ant control that the broadcast applications of nonspecific formicides has actually led to an increase in the population of the fire ants by the elimination of those species of ants and other insects which helped to keep the population of the Imported Fire Ant under control.
Drench compounds and techniques are also limited by climatic conditions, require transporting as much as five (5) gallons of water as a diluent to the individual mounds, and are of limited success due to the slow percolation of the drench material which allows many colony members, including gravid queens, to escape and to reestablish new colonies elsewhere. Juvenile Growth Hormone compounds and techniques are currently being developed, as well as biological control agents, but again, these two methods have a very limited use potential for the same basic reasons as stated above.
With respect to the state of the art of Imported Fire Ant control, U.S. Pat. No. 4,160,336, issued to Query, et al, July 10, 1979, pertains to an apparatus for treating fire ants wherein a refrigerant and an insecticide, pyrethrum, is mixed and injected as an aerosol into the individual mounds. In that treatment, Pyrethrum is injected into a Fire Ant nest along with a refrigerant. Alternatively, any other desired quick-kill, non-residual insecticide may be utilized according the Query patent.
Pyrethrum is a pyrethrin, a botanical insecticide, the active constituents of which are pyrethrins I and II (esters of pyrethrolone, chrysanthemic acid, and pyrethroic acid), and jasmolin I and II (jasmoline, chrysanthemic acid, and pyrethroic acid) collectively known as "pyrethrins". The plant Chrysanthemum cinerariaefolium and its flowers are the source of the constituents. The flowers and the extracts therefrom are principally imported from Kenya, Africa, and Ecuador, South America.
Another patent, U.S. Pat. No. 3,229,409, issued to H. D. Johnson, et al, Jan. 18, 1966, relates to hand held aerosl dispensers of insecticides. It is self evident that, although these two patents relate to the same general field of technology, the present invention is unique in its application method, and the apparatus designed to produce the desired results.
The Imported Fire Ant builds nest mounds that are some thirty (30) inches in diameter, some twenty-four (24) inches high above the ground, and extending an average of six (6) feet beneath the surface, but often extending as much as twenty (20) feet deep. They construct lateral foraging tunnels a few inches beneath the ground's surface which extend outward for an average of seventy-five (75) feet. The colonies can contain some 250-300 thousand individual ants and in areas of average infestation, the colonies number fifty (50) per acre. It is known that as many as 97 thousand new queens are produced per acre, per year, on the average. The typical life span of an egg laying queen and the colony is three to five years.
When a colony is disturbed in any manner, such as the vibration or pressure changes caused by approaching footsteps or the vibration of pouring a drench or granual bait on the mound, the entire colony can be totally evacuated in less than one minute. At the time of the first vibration, the workers immediately lead the queens deep into the central reaches of the nest or out through the various lateral tunnels and thus to safety from most attempts to kill the queens. A single, surviving queen is capable of re-establishing a colony.
Accordingly, it will be apparent that a need continues to exist for a means of treating, with the goal or eradicating, the Imported Fire Ant of the genus Solenopsis.